Ajax + java Servlet 制作Web进度条

标签：case Web java 进度条 proportion break XMLHttpRequest servlet xmlHttp

Ajax + java Servlet 制作Web进度条_java

运行效果图

Ajax + java Servlet 制作Web进度条_java_02

index2.jsp

<%@ page language="java" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <script type="text/javascript" language="javaScript">
      var bgcolor = '#0081C2'; //全局变量，用于设置进度条的背景色  
      var number; //全局变量，用于记录当前span序号
      var clear = "   "; //全局变量，记录清空时的内容
      var xmlHttp = false; //全局变量，用于记录XMLHttpRequest对象
      function createXMLHttpRequest() { //创建XMLHttpRequest对象的方法
        if(window.ActiveXObject) { //Inetrnet Explorer时，创建XMLHttpRequest对象的方法
          try {
            xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
          } catch(e) {
            try {
              xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
               //旧版本的Inetrnet Explorer，创建XMLHttpRequest对象
            } catch(e) {
              window.alert("创建XMLHttpRequest对象错误"+e);
            }
          }
        } else if(window.XMLHttpRequest) { //mozilla时，创建XMLHttpRequest对象的方法
          xmlHttp = new XMLHttpRequest();
        }
        if(!(xmlHttp)) { //未成功创建XMLHttpRequest对象
            window.alert("创建XMLHttpRequest对象异常！");
        }
      }

      //启动进度条的方法
      function startRun() {
        createXMLHttpRequest(); //创建XMLHttpRequest对象
        clearBar(); //执行请求前先清除进度条
         document.getElementById("result").innerHTML = "Running";
        xmlHttp.onreadystatechange = callBack;
        //指定onreadystatechange属性值，用于指定状态正常时的处理函数
        xmlHttp.open("GET", "/ajax_servlet_1/ProcessServlet2?flag=start", true);
       
        xmlHttp.send(null);
      }

      //开始进行进度条显示的处理函数
      function callBack() {
          //window.alert("callBack()");
        if(xmlHttp.readyState == 4) {
           if(xmlHttp.status == 200) { //status状态正常时
             setTimeout("aginRun()",1000);
            //每隔1000毫秒（1秒）执行一次“aginRun()”函数
           }
        }
      }

      //清除用于显示进度条的span的内容
      function clearBar() {
        for (var i=0;i<10;i++) { //根据span元素的id，分别清楚其显示内容
          var sp = document.getElementById("sp" + i);
          sp.innerHTML = clear; //首先清空span元素的内容
          sp.style.backgroundColor = "white"; //设置span元素的背景色
        }
      }
      //设置用于显示进度条的span元素的显示内容
      function aginRun() {
        createXMLHttpRequest(); //创建XMLHttpRequest对象
        xmlHttp.onreadystatechange = aginCallBack;
        //指定状态正常时的处理函数为“aginCallBack”
        document.getElementById("run").disabled=true; //设置按钮不可用
        xmlHttp.open("GET", "/ajax_servlet_1/ProcessServlet2?flag=run", true);
        //window.alert(" " + number);
        xmlHttp.send(null);
      }

      //进度条执行时的函数
      function aginCallBack() {
        if(xmlHttp.readyState==4) {
          if(xmlHttp.status==200) {
            var percent =
            xmlHttp.responseXML.getElementsByTagName("percent")[0].firstChild.data;
           //记录当前完成比例
            var index = parseResult(percent); //解析结果集
            var nextCell = 1;
            for (var i=0; i<index; i++) { //遍历span元素集合，设置其内容（颜色与文字）
              var sp = document.getElementById("sp"+i);
            //根据每个span元素的id获取span对象
              sp.innerHTML= clear; //清空span元素内容
              sp.style.backgroundColor = bgcolor; //设置span元素的内容
              nextCell = i+1;
              if(nextCell>=index && nextCell<10) { //显示当前处理进度的百分比
                document.getElementById("sp"+nextCell).innerHTML=percent+"%";
              }
            }
            if(index<10) { //索引小于10，设置setTimeout方法
               setTimeout("aginRun()",1000);
            } else { //索引大于10，设置进度条成功完成的页面效果
               document.getElementById("result").innerHTML = "OK!";
               document.getElementById("run").disabled = false;
            }
          }
        }
      }

      //解析结果集
      function parseResult(result) {
        if(result.length<1) {
          return 1;
        } else if(result.length==2) {
          return result.substring(0,1);
        } else {
          return 10;
        }
      }
    </script>
    <title>Ajax进度条</title>
  </head>
  <body>
   <table align="center">
            <tr>
              <td>Ajax进度条示例   <input type="button" value="开始" id="run" onclick="startRun();"/></td>
            </tr>
            <tr>
              <td>
              <div id="processBar" style="padding:1px;border:solid black 1px;">
               <span id="sp0">   </span>
               <span id="sp1">   </span>
               <span id="sp2">   </span>
               <span id="sp3">   </span>
               <span id="sp4">   </span>
               <span id="sp5">   </span>
               <span id="sp6">   </span>
               <span id="sp7">   </span>
               <span id="sp8">   </span>
               <span id="sp9">   </span>
              </div>
              </td>
            </tr>
            <tr><td align="center" id="result"></td> </tr>
    </table>
  </body>
</html>

ProcessServlet2.java

package ajax_servlet_1;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

// 

public class ProcessServlet2 extends HttpServlet {
    private static final long serialVersionUID = 5280356329609002908L;
    
    private static final String CONTENT_TYPE = "text/xml; charset=UTF-8";
//设置返回响应的ContentType
    private int count = 1;// 全局变量计数器
    /**
     *当前Servlet对象构造方法
     */
    public ProcessServlet2() {
        super();
    }
    /**
     *当前Servlet销毁时的操作。<br>
     */
    public void destroy() {
        super.destroy();
    }
    /**
     *当前Servlet的doGet方法。<br>
     *
     *当客户端表单的“method”类型为“get”时，调用此方法
     *
     * @param request客户端请求对象
     * @param response 服务器响应对象
     * @throws ServletException 发生ServeltException时抛出
     * @throws IOException发生IOException时抛出
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        System.out.println("*********************doGet()**********");
        response.setContentType(CONTENT_TYPE); //设置服务器响应类型
        response.setHeader("Cache-Control","no-cache"); //页面不记录缓存
        String flag = request.getParameter("flag"); //操作类型
        StringBuffer xml=
//            new StringBuffer("<?xml version=\"1.0\" encoding=\"UTF-8\"?><items>");
            new StringBuffer("<items>");
        //记录返回的xml串
        if("start".equals(flag)) { //第一次创建
//            xml.append("<count>1</count>");
            count = 1;
        } else {
            String proportion = "";
            try
            { 
                
                switch(count) { //根据计数器的值，设置显示当前进度的百分比
                  case 1:
                      proportion="10"; 
                      break;
                  case 2:
                      proportion="20";  
                      break;
                  case 3:
                      proportion="30"; 
                      break;
                  case 4:
                      proportion="40"; 
                      break;
                  case 5:
                      proportion="50"; 
                      break;
                  case 6:
                      proportion="60"; 
                      break;
                  case 7:
                      proportion="70"; 
                      break;
                  case 8:
                      proportion="80"; 
                      break;
                  case 9:
                      proportion="90"; 
                      break;
                  case 10:
                      proportion="100"; 
                      break;
                }
                
            }
            catch(InterruptedException e)
            { 
                e.printStackTrace(); 
            } 
            count++;
            xml.append("<percent>").append(proportion).append("</percent>");
        }
        xml.append("</items>");
        PrintWriter out = response.getWriter();
        out.println(xml.toString()); //返回生成的XML串
        out.flush(); //输出流刷新
        out.close(); //关闭输出流
        System.out.println("*********** " + xml.toString());
    }

    /**
     * 初始化servlet. <br>
     * @throws ServletException 发生ServletExcpetio异常时抛出
     */
    public void init() throws ServletException {
    }
}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <servlet>
    <servlet-name>ProcessServlet</servlet-name>
    <servlet-class>ajax_servlet_1.ProcessServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>ProcessServlet</servlet-name>
    <url-pattern>/ProcessServlet</url-pattern>
  </servlet-mapping>
  <servlet>
    <servlet-name>ProcessServlet2</servlet-name>
    <servlet-class>ajax_servlet_1.ProcessServlet2</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>ProcessServlet2</servlet-name>
    <url-pattern>/ProcessServlet2</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index2.jsp</welcome-file>
  </welcome-file-list>
</web-app>

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Ajax + java Servlet 制作Web进度条_进度条_03

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Ajax + java Servlet 制作Web进度条_xml_04

jqueryProgressBar(jb51.net)

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视频讲解java servlet ajax 进度条

https://www.iqiyi.com/w_19rs93z9rx.html

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标签：case,Web,java,进度条,proportion,break,XMLHttpRequest,servlet,xmlHttp
From： https://blog.51cto.com/emanlee/8143307

Ajax + java Servlet 制作Web进度条

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